Smart microstructured materials enable functions such as actuation, detection, transportation, and sensing with potential applications ranging from robotics and photonics to biomedical devices. Of ...the many materials systems, liquid crystal polymer networks (LCN) are fascinating owing to their ability to exhibit reversible macroscopic deformation driven by a molecular order–disorder phase transition. LCN have been increasingly explored for their utility in the design and fabrication of smart actuating devices capable of complex shape changes or motions upon external stimulation of humidity, heat, light, and other stimuli, and recent studies in this field show that their actuation complexity can be enriched and actuation performance enhanced by having some sort of microstructures. Herein, the recent progress in microstructured actuation of LCN materials with substructures in scale ranging from micrometer to millimeter is reported, placing the emphasis on the main approaches to generating a microstructure in LCN, which include patterned LC director fields, patterned chain crosslinking in LCN with uniaxial orientation of mesogens, 3D/4D printing, and replica molding. The potential applications in microstructured 3D actuators and devices as well as functional LCN surfaces are also highlighted, with an outlook on important issues and future trends in smart microstructured LCN materials and actuators.
Reported is the recent research progress in developing dynamic microstructured materials based on liquid crystal polymers that are responsive to heat or light through an order–disorder phase transition. Their design, fabrication, function, actuation, and potential applications are discussed.
The conversion and storage of solar energy to chemical energy
artificial photosynthesis holds significant potential for optimizing the energy situation and mitigating the global warming effect. ...Photocatalytic water splitting utilizing particulate semiconductors offers great potential for the production of renewable hydrogen, while this cross-road among biology, chemistry, and physics features a topic with fascinating interdisciplinary challenges. Progress in photocatalytic water splitting has been achieved in recent years, ranging from fundamental scientific research to pioneering scalable practical applications. In this review, we focus mainly on the recent advancements in terms of the development of new light-absorption materials, insights and strategies for photogenerated charge separation, and studies towards surface catalytic reactions and mechanisms. In particular, we emphasize several efficient charge separation strategies such as surface-phase junction, spatial charge separation between facets, and polarity-induced charge separation, and also discuss their unique properties including ferroelectric and photo-Dember effects on spatial charge separation. By integrating time- and space-resolved characterization techniques, critical issues in photocatalytic water splitting including photoinduced charge generation, separation and transfer, and catalytic reactions are analyzed and reviewed. In addition, photocatalysts with state-of-art efficiencies in the laboratory stage and pioneering scalable solar water splitting systems for hydrogen production using particulate photocatalysts are presented. Finally, some perspectives and outlooks on the future development of photocatalytic water splitting using particulate photocatalysts are proposed.
Achieving complex shape change of liquid‐crystal polymer networks (LCNs) under stimulation generally requires spatial configuration of the orientation direction, that is, patterned directors, of ...liquid crystal monomers prior to polymerization by means of treated surfaces. A strategy is demonstrated that needs only the simple uniaxial orientation of mesogens (monodomain) induced by mechanical stretching of LCNs. Using a rationally designed liquid crystal polymer, photocrosslinking is utilized to pattern or spatially organize the actuating monodomains in order to generate a differential contractile and/or extensional force field required for targeted shape change. Moreover, the approach enables versatile actuation modes and allows multiple shape changes to be programmed on a single piece of the polymer. This important feature is demonstrated with a specimen cut to have eight strips that, upon thermal stimulation, simultaneously display eight types of shape morphing.
Roll with the changes: An easily processable liquid crystal polymer with only uniaxial orientation of mesogens can be programmed to display multiple, complex shape morphing on a single piece of the material (eight changes are shown in the picture). The approach consists of using photocrosslinking to spatially configure and organize the actuation domains in a mechanically stretched specimen.
Commercial surrogacy is neither prohibited nor approved in China. As the underground surrogacy market keeps expanding fast, the disputes over parenthood of surrogate child occur more and more ...frequently. Since there are no specific rules for surrogacy, Chinese courts have to make legal determination by applying current laws. This article firstly analyses the contradictions of existing laws and regulations on natural parenthood when apply them in the cases of surrogacy. In China, since the natural parenthood is built on reproductive connections between parents and child, this article provides a typology of surrogacy in terms of the reproductive role each party has played. By combining it with the case study, the judicial views on different issues are presented. This article further discusses the inadequacies of current legal determination of parenthood, ethical controversies in surrogacy and recommends some suggestions on regulating the surrogacy and protecting the rights and interests of women and children.
Nicotinic acetylcholine receptors (nAChRs) are ion channels that are expressed in the cell membrane of all mammalian cells, including cancer cells. Recent findings suggest that nAChRs not only ...mediate nicotine addiction in the brain but also contribute to the development and progression of cancers directly induced by nicotine and its derived carcinogenic nitrosamines whereas deregulation of the nAChRs is observed in many cancers, and genome-wide association studies (GWAS) indicate that SNPs nAChRs associate with risks of lung cancers and nicotine addiction. Emerging evidences suggest nAChRs are posited at the central regulatory loops of numerous cell growth and prosurvival signal pathways and also mediate the synthesis and release of stimulatory and inhibitory neurotransmitters induced by their agonists. Thus nAChRs mediated cell signaling plays an important role in stimulating the growth and angiogenic and neurogenic factors and mediating oncogenic signal transduction during cancer development in a cell type specific manner. In this review, we provide an integrated view of nAChRs signaling in cancer, heightening on the oncogenic properties of nAChRs that may be targeted for cancer treatment.
Summary
Bacterial flagella and type III secretion system (T3SS) are evolutionarily related molecular transport machineries. Flagella mediate bacterial motility; the T3SS delivers virulence effectors ...to block host defenses. The inflammasome is a cytosolic multi‐protein complex that activates caspase‐1. Active caspase‐1 triggers interleukin‐1β (IL‐1β)/IL‐18 maturation and macrophage pyroptotic death to mount an inflammatory response. Central to the inflammasome is a pattern recognition receptor that activates caspase‐1 either directly or through an adapter protein. Studies in the past 10 years have established a NAIP–NLRC4 inflammasome, in which NAIPs are cytosolic receptors for bacterial flagellin and T3SS rod/needle proteins, while NLRC4 acts as an adapter for caspase‐1 activation. Given the wide presence of flagella and the T3SS in bacteria, the NAIP–NLRC4 inflammasome plays a critical role in anti‐bacteria defenses. Here, we review the discovery of the NAIP–NLRC4 inflammasome and further discuss recent advances related to its biochemical mechanism and biological function as well as its connection to human autoinflammatory disease.
Abstract
Messenger RNAs (mRNAs) shoulder special responsibilities that transmit genetic code from DNA to discrete locations in the cytoplasm. The locating process of mRNA might provide spatial and ...temporal regulation of mRNA and protein functions. The situ hybridization and quantitative transcriptomics analysis could provide detail information about mRNA subcellular localization; however, they are time consuming and expensive. It is highly desired to develop computational tools for timely and effectively predicting mRNA subcellular location. In this work, by using binomial distribution and one-way analysis of variance, the optimal nonamer composition was obtained to represent mRNA sequences. Subsequently, a predictor based on support vector machine was developed to identify the mRNA subcellular localization. In 5-fold cross-validation, results showed that the accuracy is 90.12% for Homo sapiens (H. sapiens). The predictor may provide a reference for the study of mRNA localization mechanisms and mRNA translocation strategies. An online web server was established based on our models, which is available at http://lin-group.cn/server/iLoc-mRNA/.
•An empirical study with 137 power plants in China.•Market based regulations help improve efficiency and reduce CO2 emission.•Government subsidies help improve efficiency and reduce CO2 ...emission.•Command and control regulations do not have a clear impact.•China should utilize more market based regulations in its power industry.
The power industry is the largest air polluter in China, contributing nearly 40% of CO2 emissions and 60% of SO2 emissions. Under mounting pressure to improve standards of environmental protection, it is imperative that the industry increases the efficiency and environmental performance of power plants in China. We investigate the impacts of three different environmental regulations on efficiency improvement and CO2 reduction: command and control regulations (CCR), market-based regulations (MBR), and government subsidies (GS). We find that MBR and GS have a positive impact on efficiency improvement and CO2 reduction. However, CCR have no significant impacts. This finding has important implications since CCR dominates China’s environmental policy. We discuss the policy implications of these findings, such as China should further release the potential of MBR in the power industry, instead of solely relying on CCR; and pay more attention to the coordination of different policy instruments.
Mitogen-activated protein kinase kinase 1 (MAPK kinase 1, MEK1) is a key kinase in the mitogen-activated protein kinase (MAPK) signaling pathway. MEK1 mutations have been reported to lead to abnormal ...activation that is closely related to the malignant growth and spread of various tumors, making it an important target for cancer treatment. Targeting MEK1, four small-molecular drugs have been approved by the FDA, including Trametinib, Cobimetinib, Binimetinib, and Selumetinib. Recently, a study showed that modification with dehydroalanine (Dha) can also lead to abnormal activation of MEK1, which has the potential to promote tumor development. In this study, we used molecular dynamics simulations and metadynamics to explore the mechanism of abnormal activation of MEK1 caused by the Dha modification and predicted the inhibitory effects of four FDA-approved MEK1 inhibitors on the Dha-modified MEK1. The results showed that the mechanism of abnormal activation of MEK1 caused by the Dha modification is due to the movement of the active segment, which opens the active pocket and exposes the catalytic site, leading to sustained abnormal activation of MEK1. Among four FDA-approved inhibitors, only Selumetinib clearly blocks the active site by changing the secondary structure of the active segment from α-helix to disordered loop. Our study will help to explain the mechanism of abnormal activation of MEK1 caused by the Dha modification and provide clues for the development of corresponding inhibitors.
Inflammatory caspases (caspase-1, -4, -5 and -11) are critical for innate defences. Caspase-1 is activated by ligands of various canonical inflammasomes, and caspase-4, -5 and -11 directly recognize ...bacterial lipopolysaccharide, both of which trigger pyroptosis. Despite the crucial role in immunity and endotoxic shock, the mechanism for pyroptosis induction by inflammatory caspases is unknown. Here we identify gasdermin D (Gsdmd) by genome-wide clustered regularly interspaced palindromic repeat (CRISPR)-Cas9 nuclease screens of caspase-11- and caspase-1-mediated pyroptosis in mouse bone marrow macrophages. GSDMD-deficient cells resisted the induction of pyroptosis by cytosolic lipopolysaccharide and known canonical inflammasome ligands. Interleukin-1β release was also diminished in Gsdmd(-/-) cells, despite intact processing by caspase-1. Caspase-1 and caspase-4/5/11 specifically cleaved the linker between the amino-terminal gasdermin-N and carboxy-terminal gasdermin-C domains in GSDMD, which was required and sufficient for pyroptosis. The cleavage released the intramolecular inhibition on the gasdermin-N domain that showed intrinsic pyroptosis-inducing activity. Other gasdermin family members were not cleaved by inflammatory caspases but shared the autoinhibition; gain-of-function mutations in Gsdma3 that cause alopecia and skin defects disrupted the autoinhibition, allowing its gasdermin-N domain to trigger pyroptosis. These findings offer insight into inflammasome-mediated immunity/diseases and also change our understanding of pyroptosis and programmed necrosis.
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